Concern about potential contamination is prompting the Madison Water Utility to keep a well on the city's near east side on standby through the summer.
The city said Tuesday it will not use water from Well 8 in the distribution system, but the well will be put on standby mode should water be needed for a fire or other emergency.
A groundwater monitoring well placed by Madison Kipp about 600 feet from Well 8 contains traces of the PCE tetrachloroethylene, according to the utility. This is the same chemical contaminating groundwater beneath the company's headquarters.
The utility says no PCE has ever been found in the well.
According to Madison Kipp, recent tests of the monitoring well detected PCE at very low levels of about 0.76 micrograms per liter. The federally mandated maximum contaminant level for PCE is 5.0 micrograms per liter.
Kipp has completed a modeling study showing a contamination plume emanating from the property will not reach Well 8, but the utility states that another study from the Wisconsin Geological Survey to confirm those results could take several months to complete.
Well 8 will be taken offline in September, when demand for water diminishes.